Polypeptides as apelin inhibitors and uses thereof

ABSTRACT

The present invention relates to polypeptides and their uses as apelin inhibitors. More particularly, the present invention relates to a polypeptide comprising the sequence as set forth in SEQ ID NO:1 wherein at least one arginine residue at position 18, 19, 22 or 23 has been substituted or deleted.

FIELD OF THE INVENTION

The present invention relates to polypeptides and their uses as apelininhibitors.

BACKGROUND OF THE INVENTION

The orphan receptor APJ (putative receptor protein related toangiotensin II type 1 receptor or ATI) is a G-protein coupled receptorwith seven transmembrane domains, constituted of 380 amino acids. In thesearch for an endogenous ligand of the orphan receptor APJ, a peptidecalled apelin (APJ endogenous ligand) was first isolated from bovinestomach extracts and the corresponding human protein was deduced fromthis discovery.

The apelin polypeptide is initially produced as a 77 amino acid protein(called preproapelin) that is cleaved to produce cleavage products of 36amino acids (proapelin), 17 amino acids, and 13 amino acids, each ofthem having a high affinity (in the nM range) for the APJ receptor. Thepeptide size of apelin-17 and apelin-13 are necessary and sufficient forthe ability of an apelin polypeptide to interact with APJ. Currently,the mechanism and function of apelin precursor (proapelin or apelin-36)conversion to mature apelin peptides (apelin-17 or apelin-13) are notwell known.

Apelin and APJ receptors are both widely distributed in the brain butare particularly highly expressed in the supraoptic (SON) andparaventricular (PVN) hypothalamic nuclei. Dual labelling studiesdemonstrate that within these two nuclei, apelin and its receptor arecolocalized with vasopressin (AVP) in a subset of magnocellular neurons.In lactating rats, characterized by increases in both synthesis andrelease of AVP, central injection of apelin inhibits the phasicelectrical activity of AVP neurons, decreases systemic AVP releaseinducing aqueous diuresis. Taken together, these data suggest thatapelin is a natural inhibitor of the antidiuretic effect of AVP.Moreover apelin systemically administered reduces arterial bloodpressure, increases cardiac contractility and reduces cardiac loading.

SUMMARY OF THE INVENTION

The present invention relates to a polypeptide comprising the sequenceas set forth in SEQ ID NO:1 [APELIN-36] wherein at least one arginineresidue at position 18, 19, 22 or 23 has been substituted or deleted.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a polypeptide comprising the sequenceas set forth in SEQ ID NO:1 [APELIN-36] wherein at least one arginineresidue at position 18, 19, 22 or 23 has been substituted or deleted.

In one embodiment, the polypeptide according to the invention comprisesa sequence as set forth in SEQ ID NO:2 [APELIN-77] wherein at least onearginine residue at position 59,60, 63, or 64 has been substituted ordeleted.

According to one embodiment, 1, 2, 3, or 4 arginine residues aresubstituted or deleted.

The Arginine residue substitution(s) may be performed with any aminoacid that leads to the deletion of the cleavage site and the generationof unprocessed form of apelin. Typically, the arginine residue(s) may besubstituted independently by a neutral amino acid selected from thegroup consisting of asparagine, glutamine, serine, threonine, tyrosine,glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine,methionine and tryptophane. In a particular embodiment, the arginineresidues are independently substituted by a serine residue and inanother particular embodiment all arginine residues are substituted by aserine residue.

The polypeptides of the invention may be produced by any technique knownper se in the art, such as, without limitation, any chemical,biological, genetic or enzymatic technique, either alone or incombination.

Knowing the amino acid sequence of the desired sequence, one skilled inthe art can readily produce said polypeptides, by standard techniquesfor production of polypeptides. For instance, they can be synthesizedusing well-known solid phase method, preferably using a commerciallyavailable peptide synthesis apparatus (such as that made by AppliedBiosystems, Foster City, Calif.) and following the manufacturer'sinstructions.

Alternatively, the polypeptides of the invention can be synthesized byrecombinant DNA techniques as is now well-known in the art. For example,these fragments can be obtained as DNA expression products afterincorporation of DNA sequences encoding the desired (poly)peptide intoexpression vectors and introduction of such vectors into suitableeukaryotic or prokaryotic hosts that will express the desiredpolypeptide, from which they can be later isolated using well-knowntechniques.

A further object of the present invention encompassesfunction-conservative variants of the polypeptides of the presentinvention, providing that the at least one arginine residue at position18, 19, 22 or 23 remains deleted or substituted. “Function-conservativevariants” are those in which a given amino acid residue in a protein orenzyme has been changed without altering the overall conformation andfunction of the polypeptide, including, but not limited to, replacementof an amino acid with one having similar properties (such as, forexample, polarity, hydrogen bonding potential, acidic, basic,hydrophobic, aromatic, and the like). Amino acids other than thoseindicated as conserved may differ in a protein so that the percentprotein or amino acid sequence similarity between any two proteins ofsimilar function may vary and may be, for example, from 70% to 99% asdetermined according to an alignment scheme such as by the ClusterMethod, wherein similarity is based on the MEGALIGN algorithm. A“function-conservative variant” also includes a polypeptide which has atleast 60% amino acid identity as determined by BLAST or FASTAalgorithms, preferably at least 75%, most preferably at least 85%, andeven more preferably at least 90%, and which has the same orsubstantially similar properties or functions as the native or parentprotein to which it is compared.

In a particular embodiment, the polypeptide of the invention consists orcomprises a sequence having at least 90% amino acid identity with SEQ IDNO:1 providing that the arginine residues at position 18, 19, 22 or 23has been substituted or deleted.

In a particular embodiment, the polypeptide of the invention consists orcomprises a sequence having at least 90% amino acid identity with SEQ IDNO:2 providing that the arginine residues at position 59,60, 63, or 64has been substituted or deleted.

In one embodiment, the polypeptide according to the invention comprisesa sequence as set forth in SEQ ID NO:3 (Apelin-77 mouse) wherein atleast one arginine residue at position 59,60, 63, or 64 has beensubstituted or deleted.

In one embodiment, the polypeptide according to the invention comprisesa sequence as set forth in SEQ ID NO:4 (Apelin-77 rat) wherein at leastone arginine residue at position 59,60, 63, or 64 has been substitutedor deleted.

In one embodiment, the polypeptide according to the invention comprisesa sequence as set forth in SEQ ID NO:5 (Apelin-77 beef) wherein at leastone arginine residue at position 59,60, 63, or 64 has been substitutedor deleted.

In one embodiment, the polypeptide of the invention consists orcomprises a sequence having at least 90% amino acid identity with SEQ IDNO:8 (LVQPRGSRNGPGPWQGGSSKFSSQRPRLSHKGPMPF).

In one embodiment, the polypeptide of the invention consists orcomprises a sequence as set forth in SEQ ID NO:8(LVQPRGSRNGPGPWQGGSSKFSSQRPRLSHKGPMPF).

Polypeptides of the invention can be use in an isolated (e.g., purified)form or contained in a vector, such as a membrane or lipid vesicle (e.g.a liposome).

A further object of the invention relates to a nucleic acid comprising asequence encoding for a polypeptide of the invention.

Typically, said nucleic acid is a DNA or RNA molecule, which may beincluded in any suitable vector, such as a plasmid, cosmid, episome,artificial chromosome, phage or a viral vector. The terms “vector”,“cloning vector” and “expression vector” mean the vehicle by which a DNAor RNA sequence (e.g. a foreign gene) can be introduced into a hostcell, so as to transform the host and promote expression (e.g.transcription and translation) of the introduced sequence.

So, a further object of the invention relates to a vector comprising anucleic acid of the invention.

Such vectors may comprise regulatory elements, such as a promoter,enhancer, terminator and the like, to cause or direct expression of saidpolypeptide upon administration to a subject. The vectors may furthercomprise one or several origins of replication and/or selectablemarkers. The promoter region may be homologous or heterologous withrespect to the coding sequence, and provide for ubiquitous,constitutive, regulated and/or tissue specific expression, in anyappropriate host cell, including for in vivo use. Examples of promotersinclude bacterial promoters (T7, pTAC, Trp promoter, etc.), viralpromoters (LTR, TK, CMV-IE, etc.), mammalian gene promoters (albumin,PGK, etc), and the like.

Examples of plasmids include replicating plasmids comprising an originof replication, or integrative plasmids, such as for instance pUC,pcDNA, pBR, and the like. Examples of viral vector include adenoviral,retroviral, herpes virus and AAV vectors. Such recombinant viruses maybe produced by techniques known in the art, such as by transfectingpackaging cells or by transient transfection with helper plasmids orviruses.

A further object of the present invention relates to a cell which hasbeen transfected, infected or transformed by a nucleic acid and/or avector according to the invention. The term “transformation” means theintroduction of a “foreign” (i.e. extrinsic or extracellular) gene, DNAor RNA sequence to a host cell, so that the host cell will express theintroduced gene or sequence to produce a desired substance, typically aprotein or enzyme coded by the introduced gene or sequence. A host cellthat receives and expresses introduced DNA or RNA bas been“transformed”.

The nucleic acids of the invention may be used to produce a recombinantpolypeptide of the invention in a suitable expression system. The term“expression system” means a host cell and compatible vector undersuitable conditions, e.g. for the expression of a protein coded for byforeign DNA carried by the vector and introduced to the host cell.

Common expression systems include E. coli host cells and plasmidvectors, insect host cells and Baculovirus vectors, and mammalian hostcells and vectors. Other examples of host cells include, withoutlimitation, prokaryotic cells (such as bacteria) and eukaryotic cells(such as yeast cells, mammalian cells, insect cells, plant cells, etc.).Specific examples include E. coli, Kluyveromyces or Saccharomycesyeasts, mammalian cell lines (e.g., Vero cells, CHO cells, 3T3 cells,COS cells, etc.) as well as primary or established mammalian cellcultures (e.g., produced from lymphoblasts, fibroblasts, embryoniccells, epithelial cells, nervous cells, adipocytes, etc.).

The present invention also relates to a method for producing arecombinant host cell expressing a polypeptide according to theinvention, said method comprising the steps consisting of: (i)introducing in vitro or ex vivo a recombinant nucleic acid or a vectoras described above into a competent host cell, (ii) culturing in vitroor ex vivo the recombinant host cell obtained and (iii), optionally,selecting the cells which express and/or secrete said polypeptide. Suchrecombinant host cells can be used for the production of polypeptidesaccording to the present invention, as previously described.

The invention further relates to a method of producing a polypeptideaccording to the invention, which method comprises the steps consistingof: (i) culturing a transformed host cell according to the inventionunder conditions suitable to allow expression of said polypeptide; and(ii) recovering the expressed polypeptide.

In specific embodiments, it is contemplated that the polypeptides of theinvention may be modified in order to improve their therapeuticefficacy. Such modification may be used to decrease toxicity, increasecirculatory time, or modify biodistribution. For example, the toxicityof potentially important therapeutic compounds can be decreasedsignificantly by combination with a variety of drug carrier vehiclesthat modify biodistribution.

A strategy for improving drug viability is the utilization ofwater-soluble polymers. Various water-soluble polymers have been shownto modify biodistribution, improve the mode of cellular uptake, changethe permeability through physiological barriers; and modify the rate ofclearance from the body. To achieve either a targeting orsustained-release effect, water-soluble polymers have been synthesizedthat contain drug moieties as terminal groups, as part of the backbone,or as pendent groups on the polymer chain.

Polyethylene glycol (PEG) has been widely used as a drug carrier, givenits high degree of biocompatibility and ease of modification. Attachmentto various drugs, proteins, and liposomes has been shown to improveresidence time and decrease toxicity. PEG can be coupled to activeagents through the hydroxyl groups at the ends of the chain and viaother chemical methods; however, PEG itself is limited to at most twoactive agents per molecule. In a different approach, copolymers of PEGand amino acids may also be suitable because they retain thebiocompatibility properties of PEG, but they have the added advantage ofnumerous attachment points per molecule (providing greater drugloading), and which could be synthetically designed to suit a variety ofapplications. Those of skill in the art are aware of PEGylationtechniques for the effective modification of drugs. For example, drugdelivery polymers that consist of alternating polymers of PEG andtri-functional monomers such as lysine have been used. The PEG chains(typically 2000 daltons or less) are linked to the a- and e-amino groupsof lysine through stable urethane linkages. Such copolymers retain thedesirable properties of PEG, while providing reactive pendent groups(the carboxylic acid groups of lysine) at strictly controlled andpredetermined intervals along the polymer chain. The reactive pendentgroups can be used for derivatization, cross-linking, or conjugationwith other molecules. These polymers are useful in producing stable,long-circulating pro-drugs by varying the molecular weight of thepolymer, the molecular weight of the PEG segments, and the cleavablelinkage between the drug and the polymer. The molecular weight of thePEG segments affects the spacing of the drug/linking group complex andthe amount of drug per molecular weight of conjugate (smaller PEGsegments provides greater drug loading). In general, increasing theoverall molecular weight of the block co-polymer conjugate will increasethe circulatory half-life of the conjugate. Nevertheless, the conjugatemust either be readily degradable or have a molecular weight below thethreshold-limiting glomular filtration (e.g., less than 45 kDa).

A further object of the invention relates to a polypeptide of theinvention as an apelin inhibitor.

The role of apelin in the pathophysiology of various diseases has beendescribed in Pitkin S L, Maguire J J, Bonner T I, Davenport A P.International Union of Basic and Clinical Pharmacology. LXXIV. Apelinreceptor nomenclature, distribution, pharmacology, and function.Pharmacol Rev. 2010 September; 62(3):331-42. Epub 2010 Jul. 6. Review.

Accordingly, the polypeptides according to the invention may be suitablefor the modulation of central nervous system function (vasopressinneuron activity and systemic vasopressin release, drinking behaviour,food intake), cardiovascular function (blood pressure, myocardiumcontractibility), immune function, gastrointestinal function, metabolicfunction, reproductive function, etc. . . . , and therefore, can be usedas a therapeutic and/or prophylactic agent for a variety of diseases.

The present invention thus a method for treating and/or preventing adisease, condition or disorder mediated by the apelin in mammals, suchmethod involving the step of administering to a mammal in need thereof atherapeutically effective amount of a polypeptide of the presentinvention or a pharmaceutical composition thereof.

Diseases, conditions and/or disorders which could be treated orprevented by the administration of a polypeptide of the invention arefor example:

-   -   Inappropriate vasopressin secretions (SIADH) including        pathologies like neurogenic diabetes mellitus (e.g. diabetic        complications such as diabetic nephropathy, diabetic neuropathy,        diabetic retinopathy, etc.), lung cancer, septic choc, thirst        troubles;    -   Cardiovascular diseases: Heart failure, diseases of kidney (e.g.        renal failure, nephritis, etc.) hypertension, cirrhosis,        arteriosclerosis, pulmonary emphysema, pulmonary oedema;    -   Metabolic diseases: Obesity, anorexia, hyperphagia, polyphagia,        hypercholesterolemia, hyperglyceridemia, hyperlipemia;    -   Various types of dementia such as senile dementia,        cerebrovascular dementia, dementia due to genealogical        denaturation degenerative diseases (e.g. Alzheimer's disease,        Parkinson's disease, Pick's disease, Huntington's disease,        etc.), dementia resulting from infectious diseases (e.g. delayed        virus infections such as Creutzfeldt-Jakob disease), dementia        associated with endocrine diseases, metabolic diseases, or        poisoning (e.g. hypothyroidism, vitamin B12 deficiency,        alcoholism, poisoning caused by various drugs, metals, or        organic compounds), dementia caused by tumors (e.g. brain        tumor), and dementia due to traumatic diseases (e.g. chronic        subdural hematoma), depression, hyperactive child syndrome        (microencephalopathy), disturbance of consciousness, anxiety        disorder, schizophrenia, phobia;    -   Growth hormone secretory disorder (e.g. gigantism, acromegaly,        etc.), hyperprolactinemia. galactorrhea.    -   Cancer (e.g. mammary cancer, lymphocytic leukemia, bladder        cancer, ovary cancer, carcinoma of prostate, etc.);    -   And pancreatitis, Turner's syndrome, neurosis, rheumatoid        arthritis, spinal cord injury, transient brain ischemia,        amyotrophic lateral sclerosis, spinocerebellar degeneration,        bone fracture, wounds, atopic dermatitis, osteoporosis, asthma,        epilepsy, sterility.

The polypeptide of the invention may be used as a postoperativenutritional status improving agent or as an inotropic agent,vasodilatator or an aqueous diuretic.

In a particular embodiment, the polypeptide of the invention may usedfor the inhibition of the anti-aggregant function of apelin.

In another embodiment, the polypeptide of the invention may be used forthe treatment of angiogenic diseases.

An “angiogenic disease” is a disease associated with unregulatedangiogenesis. Typically, angiogenic diseases include but are not limitedto primary and metastatic solid tumors, including carcinomas of breast,colon, rectum, lung, oropharynx, hypopharynx, esophagus, stomach,pancreas, liver, gallbladder and bile ducts, small intestine, kidney,bladder, urothelium, female genital tract, (including cervix, uterus,and ovaries as well as choriocarcinoma and gestational trophoblasticdisease), male genital tract (including prostate, seminal vesicles,testes and germ cell tumors), endocrine glands (including the thyroid,adrenal, and pituitary glands), and skin, as well as hemangiomas,melanomas, sarcomas (including those arising from bone and soft tissuesas well as Kaposi's sarcoma) and tumors of the brain, nerves, eyes, suchas astrocytomas, gliomas, glioblastomas, retinoblastomas, neuromas,neuroblastomas, Schwannomas, and meningiomas. Angiogenic diseases alsorelate to tumors arising from hematopoietic malignancies such asleukemias as well both Hodgkin's and non-Hodgkin's lymphomas. Angiogenicdiseases also pertain to rheumatoid, immune and degenerative arthritis;various ocular diseases such as diabetic retinopathy, retinopathy ofprematurity, corneal graft rejection, retrolental fibroplasia,neovascular glaucoma, rubeosis, retinal neovascularization due tomacular degeneration (e.g. age-related macular degeneration), hypoxia,angiogenesis in the eye associated with infection or surgicalintervention, and other abnormal neovascularization conditions of theeye. Angiogenic diseases further include skin diseases such aspsoriasis; blood vessel diseases such as hemagiomas, and capillaryproliferation within atherosclerotic plaques; Osler-Webber Syndrome;myocardial angiogenesis; plaque neovascularization; telangiectasia;hemophiliacjoints'; angiofibroma; and wound granulation. Otherangiogenic diseases include diseases characterized by excessive orabnormal stimulation of endothelial cells, including but not limited tointestinal adhesions, Crohn's disease, atherosclerosis, scleroderma, andhypertrophic scars, i.e. keloids, diseases that have angiogenesis as apathologic consequence such as cat scratch disease (Rochele ninaliaquintosa) and ulcers (Helicobacter pylori).

The polypeptide of the invention is used for the reduction ofangiogenesis. The amount effective to reduce angiogenesis correspond toat least a reduction of about 15%-80%, or more, when compared to controluntreated subject or a placebo-treated control.

For cancer treatments, the polypeptide of the invention may be used forthe treatment of both primary and metastatic tumors where theangiogenesis is a crucial process. Accordingly, the polypeptide of theinvention may be useful for metastases inhibition that are originatedfrom the tumors described above. The polypeptide of the invention may beused alone or in combination with adjunct therapy including radiotherapyand/or chemotherapy.

The polypeptide of the invention may be used in combination with anytherapeutical agent. For example the polypeptide of the invention may beadministered with one or more other therapeutic agents, such as cancerchemotherapeutic agent; VEGF antagonist. The polypeptide may beadministered prior to, concurrently, or after other substance ortherapy. The polypeptide may be administered as an adjuvant therapy to astandard cancer therapy such as surgery, radiation, bone marrowtransplantation, chemotherapeutic treatment.

The polypeptide of the invention may be combined with pharmaceuticallyacceptable excipients, and optionally sustained-release matrices, suchas biodegradable polymers, to form pharmaceutical compositions.

In the pharmaceutical compositions of the present invention for oral,sublingual, subcutaneous, intramuscular, intravenous, transdermal, localor rectal administration, the active principle, alone or in combinationwith another active principle, can be administered in a unitadministration form, as a mixture with conventional pharmaceuticalsupports, to animals and human beings. Suitable unit administrationforms comprise oral-route forms such as tablets, gel capsules, powders,granules and oral suspensions or solutions, sublingual and buccaladministration forms, aerosols, implants, subcutaneous, transdermal,topical, intraperitoneal, intramuscular, intravenous, subdermal,transdermal, intrathecal and intranasal administration forms and rectaladministration forms.

Preferably, the pharmaceutical compositions contain vehicles which arepharmaceutically acceptable for a formulation capable of being injected.These may be in particular isotonic, sterile, saline solutions(monosodium or disodium phosphate, sodium, potassium, calcium ormagnesium chloride and the like or mixtures of such salts), or dry,especially freeze-dried compositions which upon addition, depending onthe case, of sterilized water or physiological saline, permit theconstitution of injectable solutions.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions; formulations including sesame oil,peanut oil or aqueous propylene glycol; and sterile powders for theextemporaneous preparation of sterile injectable solutions ordispersions. In all cases, the form must be sterile and must be fluid tothe extent that easy syringability exists. It must be stable under theconditions of manufacture and storage and must be preserved against thecontaminating action of microorganisms, such as bacteria and fungi.

Solutions comprising compounds of the invention as free base orpharmacologically acceptable salts can be prepared in water suitablymixed with a surfactant, such as hydroxypropylcellulose. Dispersions canalso be prepared in glycerol, liquid polyethylene glycols, and mixturesthereof and in oils. Under ordinary conditions of storage and use, thesepreparations contain a preservative to prevent the growth ofmicroorganisms.

The polypeptides can be formulated into a composition in a neutral orsalt form. Pharmaceutically acceptable salts include the acid additionsalts (formed with the free amino groups of the protein) and which areformed with inorganic acids such as, for example, hydrochloric orphosphoric acids, or such organic acids as acetic, oxalic, tartaric,mandelic, and the like. Salts formed with the free carboxyl groups canalso be derived from inorganic bases such as, for example, sodium,potassium, ammonium, calcium, or ferric hydroxides, and such organicbases as isopropylamine, trimethylamine, histidine, procaine and thelike.

The carrier can also be a solvent or dispersion medium containing, forexample, water, ethanol, polyol (for example, glycerol, propyleneglycol, and liquid polyethylene glycol, and the like), suitable mixturesthereof, and vegetables oils. The proper fluidity can be maintained, forexample, by the use of a coating, such as lecithin, by the maintenanceof the required particle size in the case of dispersion and by the useof surfactants. The prevention of the action of microorganisms can bebrought about by various antibacterial and antifungal agents, forexample, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, andthe like. In many cases, it will be preferable to include isotonicagents, for example, sugars or sodium chloride. Prolonged absorption ofthe injectable compositions can be brought about by the use in thecompositions of agents delaying absorption, for example, aluminiummonostearate and gelatin.

Sterile injectable solutions are prepared by incorporating the activepolypeptides in the required amount in the appropriate solvent withseveral of the other ingredients enumerated above, as required, followedby filtered sterilization. Generally, dispersions are prepared byincorporating the various sterilized active ingredients into a sterilevehicle which contains the basic dispersion medium and the requiredother ingredients from those enumerated above. In the case of sterilepowders for the preparation of sterile injectable solutions, thepreferred methods of preparation are vacuum-drying and freeze-dryingtechniques which yield a powder of the active ingredient plus anyadditional desired ingredient from a previously sterile-filteredsolution thereof.

Upon formulation, solutions will be administered in a manner compatiblewith the dosage formulation and in such amount as is therapeuticallyeffective. The formulations are easily administered in a variety ofdosage forms, such as the type of injectable solutions described above,but drug release capsules and the like can also be employed.

For parenteral administration in an aqueous solution, for example, thesolution should be suitably buffered if necessary and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous,intramuscular, subcutaneous and intraperitoneal administration. In thisconnection, sterile aqueous media which can be employed will be known tothose of skill in the art in light of the present disclosure. Forexample, one dosage could be dissolved in 1 ml of isotonic NaCl solutionand either added to 1000 ml of hypodermoclysis fluid or injected at theproposed site of infusion. Some variation in dosage will necessarilyoccur depending on the condition of the subject being treated. Theperson responsible for administration will, in any event, determine theappropriate dose for the individual subject.

The polypeptides may be formulated within a therapeutic mixture tocomprise about 0.0001 to 1.0 milligrams, or about 0.001 to 0.1milligrams, or about 0.1 to 1.0 or even about 10 milligrams per dose orso. Multiple doses can also be administered. For the treatment the doseof the polypeptide that will be used depends on the severity of thedisease, the age and the weight of the patient and the routes ofadministration and the duration of the treatment. The frequency ofadministration of the polypeptide may vary depending on the severity ofthe disease. For example, the polypeptide is administered once every 3months, once every 3 months, once every 2 months, once every month,twice per month or three times per month. The polypeptide can be alsoadministrated daily, twice a day, or more. Under certain conditions thepolypeptide is administered continuously. The period of time over whichthe polypeptide is administered, can vary, depending on any of a varietyof factors, e.g., severity of the diseases, age of patient and responseof the patient to the treatment.

In addition to the compounds of the invention formulated for parenteraladministration, such as intravenous or intramuscular injection, otherpharmaceutically acceptable forms include, e.g. tablets or other solidsfor oral administration; liposomal formulations; time release capsules;and any other form currently used.

The invention will be further illustrated by the following figures andexamples. However, these examples and figures should not be interpretedin any way as limiting the scope of the present invention.

FIGURES

FIGS. 1A and 1B shows the schematic representation of Apelin-77,Apelin-36, Apelin-17 and Apelin-13 (A) and the sequences of Apelin-77 invarious animal species (B).

FIG. 2: Human apelin cDNA encodes a protein of 77 amino acid residues.Newly synthesized apelin is a preproprotein that is proteolyticallyprocessed in order to generate mature 36, 17 and 13 amino acid forms. Wecloned human apelin into pIRES2-eGFP vector adding a V5 tag inC-terminus of the apelin sequence. Upon examination of the amino acidsequence of the apelin precursor, two dibasic motifs were recognized bythe proprotein convertases (PCs) (RRK and FRRQR) suggesting theinvolvement of these convertases in the maturation of apelin. Toidentify the PCs involved in apelin processing, apelin and each of thePCs were transiently co-expressed in LoVo cells, a furin-deficient cellline. Supernatants were collected 24 hours after transfection andanalyzed for proapelin processing by immunoblotting using a V5 antibody.As illustrated in (a), analyses of media derived from LoVo cellscotransfected with vector encoding proapelin and control vector show aband with an apparent molecular mass of 8-9 kDa, corresponding to theintact apelin precursor. Cotransfection of cells with apelin and vectorsencoding different convertase (furin, PACE4, PC5 or PC7) revealed thatonly the expression of furin is associated with a reduction in the levelof the immunoreactive precursor with a concomitant appearance of 2products of 3-4 and 2-3 kDa, corresponding to apelin-17 and apelin-13.

FIG. 3: Expression in HEK293 cells apelin and/or PCs inhibitors the PCsprosegments (profurin, proPC5) and the furin-motif variants ofα1-antitrypsin (α1-PDX) indicates that the expression in HEK293 cellswith apelin alone resulted in 100% processing, whereas, cotransfectionof cells with apelin and PCs inhibitors inhabited the processing ofapelin.

FIG. 4: HEK293 cells were transfected with wild-type or mutants apelin(mut1, mut 2), and media derived from these cells were analyzed byWestern blotting. The mutation 1 (mut1) indicates a mutation at thefirst cleavage site of Apelin (RR60K) and the mutation 2 (mut2)indicates a mutation at the second cleavage site of apelin (RR64QR).Expression of these cells with wild type Apelin, mut1 or mut2 don'taffect the processing of Apelin. Whereas the expression in these cellsof Apelin with two mutated sites prevented the processing of Apelin.Only the unprocessed form is detected under these conditions.

FIG. 5: APJ antagonist (F13A) and unprocessed double mutant apelin-36(apelin-DM) confirm the role of APJ in the inhibition of plateletfunction by apelin. Thrombin-induced aggregation of human plateletspreincubated with PBS, as control (black bar); F13A (100 nM; white bar);apelin (10 nM; grey bar) or F13A (100 nM) plus apelin (10 nM) (dashedbar).

FIG. 6: APJ antagonist (F13A) and unprocessed double mutant apelin-36(apelin-DM) confirm the role of APJ in the inhibition of plateletfunction by apelin. Intracellular Ca²⁺ mobilization ([Ca²⁺]_(i)) inhuman platelets was monitored in real-time using a fluorescencespectrophotometer. Human platelets, loaded with Fura-2-AM werepreincubated 3 minutes with PBS, as control (black bar); F13A (100 nM;white bar); apelin (10 nM; grey bar) or F13A (100 nM) plus apelin (10nM) (dashed bar) before stimulation by thrombin (100 mU/mL). While F13Aalone has no effects on tail bleeding time, platelet aggregation andCa²⁺ mobilization, its injection with apelin prevents the inhibitoryeffects of apelin alone.

FIG. 7: APJ antagonist (F13A) and unprocessed double mutant apelin-36(apelin-DM) confirm the role of APJ in the inhibition of plateletfunction by apelin. Tail bleeding time in wild-type mice receiving anintravenous injection of PBS, as control (); F13A (500 nmol/kg; ▪);apelin (50 nmol/kg; ∘) or F13A (500 nmol/kg) plus apelin (50 nmol/kg)(□).

FIG. 8: APJ antagonist (F13A) and unprocessed double mutant apelin-36(apelin-DM) confirm the role of APJ in the inhibition of plateletfunction by apelin. Tail bleeding time in wild-type mice receiving anintravenous injection of PBS, as control (); apelin (50 nmol/kg; ∘);apelin-36 (500 nmol/kg; Δ); apelin-DM (500 nmol/kg; ▪), apelin-36 plusapelin (▴) or apelin-DM plus apelin (□).

FIG. 9: HUVEC proliferation and motility. HUVEC were serum deprivedovernight and then treated for 24 h with or without VEGF in the presenceof apelin wild-type (10 ng/ml) and/or apelin mut-36 (10 ng/ml). Cellproliferation was assessed using Cell Titer96 non-radioactive cellproliferation assay.

EXAMPLE 1

Methods:

Unprocessed Mutant Apelin (Apelin-DM) Peptide Synthesis:

The unprocessed mutant of apelin (apelin-DM) was synthesized byEurogentec. During peptide synthesis the two cleavage sites of proapelin(₁₈RRKFRR) were replaced by ₁₈SSKFSS amino acid sequence to generate theapelin-DM mutant peptide:

(SEQ ID NO: 8) LVQPRGSRNGPGPWQGGSSKFSSQRPRLSHKGPMPF.

Preparation of Washed Platelets:

Human Platelets

Venous blood was collected from healthy donors on 10% (v/v) trisodiumcitrate (3.8%). Written informed consent was obtained from all thedonors. Platelet-rich plasma (PRP) was obtained by centrifugation (120g; 15 minutes; 20° C.) and platelets were isolated by differentialcentrifugation as previously described¹⁵. The platelet pellet wasresuspended in modified Tyrode-HEPES buffer without CaCl₂ (137 mM NaCl,2 mM KCl, 0.3 mM NaH₂PO₄, 5.5 mM glucose, 5 mM Hepes, 12 mM NaHCO₃, pH7.3).

Mouse Platelets

Mice were anesthetized by intraperitoneal injection of sodiumpentobarbital (60 mg/kg). Xylocain® (0.5% v/v) was used as a localanalgesic. Whole blood was collected by cardiac puncture and mixed with80 μM PPACK and 10% (v/v) ACD-C buffer (124 mM sodium citrate, 130 mMcitric acid, 110 mM dextrose, pH 6.5) to prevent coagulation.Platelet-rich plasma (PRP) was obtained by centrifugation whole bloodfor 7 minutes at 160 g. Platelets were obtained from PRP bycentrifugation for 10 minutes at 670 g and washed in the presence ofapyrase (100 mU/mL) and PGE₁ (1 μM) to minimize platelet activation,then resuspended in modified Tyrode-HEPES buffer without CaCl₂ ¹⁶.

Haematological Analysis and Bleeding Time:

Complete blood counts and haematocrit were determined with an automaticcell counter, using the standard parameters for mice. Bleeding timeassays were performed on overnight fasted animals, after injection ofPBS, apelin-13, apelin-36, apelin-DM or F13A into the retro-orbitalplexus, by cutting off the tip of the tail (3 mm from the tip) andimmediately immersing it in saline at 37° C. We then recorded the timetaken for the bleeding to stop. Tail bleeding was monitored for at least60 seconds beyond this time point, to ensure that bleeding did not beginagain. Tail bleeding assays were stopped at 600 seconds if the bleedingdid not stop.

Platelet Aggregation:

Platelet aggregation was monitored by measuring light transmissionthrough the stirred suspension of washed platelets (3×10⁸/mL) at 37° C.in presence of 1 mM CaCl₂ using a Chronolog aggregometer (Chrono-logCorporation, USA). When mentioned, platelets were first incubated withapelin-13, apelin-36, apelin-DM or F13A for 3 minutes at 37° C. Plateletaggregation was triggered by adding collagen, thrombin, or ADP.Representative traces for aggregation were obtained from at least threeindependent experiments. Results are expressed as the percent change inlight transmission with respect to the blank (buffer without platelets),set at 100%.

In Vitro Thrombus Formation Under Flow Conditions:

Thrombus formation was evaluated in a whole-blood perfusion assay on afibrillar collagen matrix under arterial shear conditions (shear rate of1000 s⁻¹) as previously described¹⁶. Briefly, glass microcapillary tubes(Vitrocom Hollow Rectangle capillaries; Fiber Optic Center, New Bedford,Mass.) were coated with fibrillar collagen (50 μg/mL; overnight; 4° C.).Blood samples were collected in 80 μM PPACK, fluorescently labelled withrhodamine 6G (10 μg/mL) and incubated for 5 minutes with PBS orapelin-13. Labelled whole blood was then perfused through the coatedglass microcapillary with a KD Scientific syringe pump (Fisher BioblockScientific, Illkirch, France). Real-time thrombus formation was recordedwith an inverted epifluorescence microscope (Nikon Eclipse TE2000-U;Champigny sur Marne, France), coupled to Metamorph 7.0r1 software(Universal Imaging Corporation). Thrombus formation was determined asthe mean fluorescence intensity (MFI).

Measurement of Intracellular Free Ca²⁺ Concentration ([Ca^(2+]) _(i)):

Human platelets were loaded with Fura-2 by incubation with 2 μMFura-2-AM for 45 minutes at 37° C. Cells were then collected bycentrifugation at 350 g for 15 min and resuspended in HEPES-bufferedsaline (145 mM NaCl, 10 mM HEPES, 10 mM D-glucose, 5 mM KCl, 1 mM MgSO₄,pH 7.4), and supplemented with 0.1% (w/v) BSA. Fluorescence was recordedfrom 2 mL aliquots of magnetically stirred cell suspensions at 37° C.using a fluorescence spectrophotometer (Varian Ltd., Madrid, Spain) withexcitation wavelengths of 340 and 380 nm and emission at 505 nm. Changesin [Ca²⁺]_(i) were monitored using the Fura-2 340/380 fluorescence ratioand calibrated according to the method of Grynkiewicz et al.¹⁹. Ca²⁺release by thrombin was estimated using the integral of the rise in[Ca²⁺]_(i) for 2.5 minutes after its addition, taking a sample everysecond, and was expressed in nM as previously described²⁰.

Statistical Analysis:

Statistical significance was evaluated with Student's t tests,two-tailed Mann-Whitney U-tests or 1-way ANOVA followed by Turkey testas indicated, using GraphPad Prism statistical software (San Diego,Calif.).

Results:

Identified as the endogenous ligand of APJ, a ubiquitously expressed Gprotein coupled receptor; Apelin exerts multiple physiological effectsin the cardiovascular system, fluid homeostasis, and adipoinsular axis.Deregulation of Apelin expression and/or activity was linked to variousdiseases, including heart failure, atherosclerosis, type 2 diabetes, andobesity. However, the mechanism and function of Apelin precursor(proApelin) conversion to mature Apelin peptides namely: apelin-36,apelin-17 and apelin-13 are not well known (FIG. 1). After removal ofthe signal peptide, the proteolytic cleavages of proApelin occur withinbasic motifs, suggesting the involvement of proprotein convertase (PC)family members in this process. Using cell transfection experiments, theprocessing of proApelin was found to be inhibited by the Furininhibitors serpin alpha1-antitrypsin (alpha1-PDX) and prosegmentproFurin (ppFurin) and proPC5 (ppPCS). Site-directed mutagenesisanalysis confirmed the RR(60)KF and KFRR(64)QR preApelin cleavage sites(FIG. 1A). In parallel, the lack of proApelin processing found in the PCactivity-deficient cell line LoVo was restored by the expression ofFurin, but not by paired basic amino acid cleaving enzyme 4 (PACE4), PC5or PC7 (FIG. 2).

To investigate the effect of the mutant Apelin peptide (DM) on Apelinfunctions, we analyzed its role on the recently identified function ofapelin on platelet aggregation. Pretreatment of human platelet bythrombin induced their aggregation and Ca2+ mobilisation. In thepresence of mature apelin-13 or proApelin (Apelin-36), these plateletfunctions were inhibited. Whereas platelet incubation with the APJreceptor antagonist apelin-13(F13A) and the synthetic unprocessed doublemutant Apelin peptide (Apelin-DM) abolished the apelin inhibitory effecton thrombin-induced aggregation and Ca2+ mobilisation (FIG. 4).Accordingly, using mice tail-bleed assay, we found that intravenousinjection of apelin-13 or Apelin-36 induced a significant increase inbleeding time. This effect was inhibited by F13A and Apelin-DM (FIG. 5).The use of RT-PCR and immunoblotting analysis revealed that humanplatelet express apelin and its receptor APJ, at the RNA and proteinlevels. In these cells the furin was also expressed. Our findingsdemonstrate the processing of Apelin by furin and highlight thepotential use of unprocessed mutant Apelin peptide as agent formetabolic disorders treatment through platelet aggregation inhibitionthat possess a functional apelin/APJ system.

EXAMPLE 2

We found that the synthetic apelin mutant peptide (SEQ ID NO: 8)inhibits endothelial cell proliferation and migration induced by VEGF(FIG. 5).

Using synthetic active apelin-13 and unprocessed mutant apelin we foundthat while apelin-13 induced the formation of new vessels, the latterprevents the neo-vascularisation as assessed by the chickchorioallantoic membrane (CAM) and mouse aortic ring assays. Inconclusion while active apelin-13 aa induced the formation of newvessels, the addition of the unprocessed mutant apelin blocked thisprocess.

Similarly, the use of the cutaneous reverse passive Arthus reactionsassay revealed that while apelin increased tissue inflammation, themutant unprocessed apelin inhibited these processes.

Taken together, these findings indicate the ability of the apelin mutantpeptide to mediate in vitro and in vivo biological actions. We nowevaluate the potential use of this newly identified inhibitor and/orderivates in tumor angiogenesis and lymphangiogenesis therapy.

REFERENCES

Throughout this application, various references describe the state ofthe art to which this invention pertains. The disclosures of thesereferences are hereby incorporated by reference into the presentdisclosure.

1. A polypeptide comprising the sequence as set forth in SEQ ID NO:1 ora function conservative variant thereof wherein at least one arginineresidue at position 18, 19, 22 or 23 has been substituted or deleted. 2.The polypeptide according to claim 1 which comprises a sequence as setforth in SEQ ID NO:2 or a function conservative variant wherein at leastone arginine residue at position 59,60, 63, or 64 has been substitutedor deleted.
 3. The polypeptide according to claim 1 wherein 1, 2, 3, or4 arginine residues are substituted or deleted.
 4. The polypeptideaccording to claim 1 wherein the arginine residue(s) are substitutedindependently by a neutral amino acid selected from the group consistingof asparagine, glutamine, serine, threonine, tyrosine, glycine, alanine,valine, leucine, isoleucine, proline, phenylalanine, methionine andtryptophane.
 5. The polypeptide according to claim 1 wherein thearginine residues are independently substituted by a serine residue. 6.The polypeptide according to claim 1 wherein the arginine residues areall substituted by a serine residue.
 7. (canceled)
 8. A method oftreating an angiogenic disease in a subject in need thereof comprisingadministering to the subject a therapeutic amount of a polypeptidecomprising a sequence as set forth in SEQ ID NO:1 or a functionconservative variant thereof wherein at least one arginine residue atposition 18, 19, 22 or 23 has been substituted or deleted. 9-12.(canceled)
 13. A method of producing a polypeptide comprising the stepsof: (i) culturing a transformed host cell comprising I) a nucleic acidcomprising a sequence encoding a polypeptide comprising a sequence asset forth in SEQ ID NO:1 or a function conservative variant thereofwherein at least one arginine residue at position 18, 19, 22 or 23 hasbeen substituted or deleted, or II) a vector comprising the nucleicacid, said step of culturing being carrier out under conditions suitableto allow expression of said polypeptide; and (ii) recovering theexpressed polypeptide.
 14. The method of claim 8, wherein saidangiogenic disease is cancer.